diff --git a/diffrax/__init__.py b/diffrax/__init__.py
index 381eec2a..9b13acdf 100644
--- a/diffrax/__init__.py
+++ b/diffrax/__init__.py
@@ -93,4 +93,4 @@
 )
 
 
-__version__ = "0.3.1"
+__version__ = "0.4.0"